In the related art, an exhaust gas purification apparatus for an internal combustion engine that burns and removes particulate matter including carbon microparticles discharged into an exhaust passage of the internal combustion engine by a single mode microwave particulate combustion apparatus has been studied. The single mode microwave particulate combustion apparatus includes a microwave generator configured to oscillate microwaves, a microwave transmitter configured to transmit the microwaves oscillated from the microwave generator into the exhaust passage, and a standing wave generating space part provided downstream of a connecting portion with the microwave transmitter.
The standing wave generating space part is configured to include an introducing port on one end and configured to pass an exhaust gas together with the microwave, a reflecting board on the other end and configured to reflect the microwave in a direction opposite to an exhaust flow direction, and a particulate deposition part configured to allow the particulate matter in the exhaust gas to deposit so that the deposited particulate matter is heated and burned by microwave energy.
Further, an isolator is disposed in the microwave transmitter configured to transmit the microwave generated in the microwave generator (see, e.g., Patent Document 1).